tau

• POS: Noun

CIDE DICTIONARY

tau, n. [Gr. tay^.].

 The nineteenth letter (t.  [Webster 1913 Suppl.]

tau, n. [Gr. tay^ the letter T).].

 The common American toadfish; -- so called from a marking resembling the Greek letter tau (1913 Webster]

Tau cross. See Illust. 6, of Cross.

OXFORD DICTIONARY

tau, n. the nineteenth letter of the Greek alphabet (T).

Idiom

tau cross a T-shaped cross. tau particle Physics an unstable, heavy, and charged elementary particle of the lepton class.

Etymology

ME f. Gk